Self-magnetizing motor and compressor having the same

Abstract

A self magnetizing motor and a compressor having the same is configured to require a lower starting voltage and to deliver superior performance. In the self magnetizing motor, a magnetic material on an exterior of the rotor is magnetized when power is supplied to a magnetizing unit of the stator. A plurality of conductive bars are inserted on the outer circumference of the rotor core. A spacing distance between outer portions of the conductive bars and inner circumference of the magnetizable material is longer than an air gap between the stator and the rotor. As a result, a magnetic strength of the magnetic material may be increased.

1. A motor, comprising:
 a stator; 
 a rotor mounted inside the stator, the rotor comprising:
 a cylindrical rotor core; 
 a magnetic material that surrounds an exterior surface of the cylindrical rotor core such that the magnetic material defines an exterior cylindrical surface of the rotor and a separation air gap “G” is maintained between an exterior surface of the magnetic material and a corresponding interior surface of the stator; and 
 a plurality of conductive bars arranged along the circumference of the cylindrical rotor core, wherein a spacing distance “t” is maintained between and outermost tip of the each of the conductive bars and a corresponding interior surface of the magnetic material, and wherein the spacing distance t is greater than the air gap G; and 
 
 a magnetizing unit that can selectively magnetize the magnetic material, wherein the magnetizing unit is mounted adjacent to the exterior cylindrical surface of the rotor, the magnetizing unit comprising:
 a plurality of magnetizing poles each having an end adjacent to the exterior cylindrical surface of the rotor; and 
 a corresponding plurality of magnetizing coils each wound around a respective magnetizing pole. 
 
 
   
   
     2. The motor of  claim 1 , wherein the magnetic material has a cylindrical shape. 
   
   
     3. The motor of  claim 2 , wherein the magnetic material comprises a plurality of bands of material that are mounted on the cylindrical core along the axial direction. 
   
   
     4. The motor of  claim 3 , wherein the plurality of bands comprises between 3 and 5 bands of magnetic material. 
   
   
     5. The motor of  claim 1 , wherein the magnetic material comprises a neodymium bonded magnetic material. 
   
   
     6. The motor of  claim 1 , wherein the air gap G is approximately 0.3 mm, and wherein the spacing distance t is between approximately 0.6 mm and approximately 1.5 mm. 
   
   
     7. The motor of  claim 6 , wherein the rotor core has a diameter of between approximately 55 mm and approximately 60 mm, and wherein each of the conductive bars has a cross-sectional area of between approximately 21 mm 2  and approximately 25 mm 2 . 
   
   
     8. The motor of  claim 7 , wherein the plurality of conductive bars comprises between 24 and 30 conductive bars in the rotor. 
   
   
     9. The motor of  claim 8 , wherein the stator has 24 slots. 
   
   
     10. The motor of  claim 1 , wherein the separation air gap G and the separation distance t satisfy the formula 2G≦t≦6G. 
   
   
     11. The motor of  claim 1 , wherein the separation air gap G and the separation distance t satisfy the formula 3G≦t≦4G. 
   
   
     12. A compressor comprising the motor of  claim 1 . 
   
   
     13. A motor, comprising:
 a stator; 
 a rotor mounted inside the stator, the rotor comprising:
 a cylindrical rotor core having a diameter of between approximately 55 mm and approximately 60 mm; 
 a magnetic material mounted on an exterior surface of the cylindrical rotor core so as to define an exterior cylindrical surface of the rotor; and 
 a plurality of conductive bars arranged along the circumference of the cylindrical rotor core, wherein each of the conductive bars has a cross-sectional area of between approximately 21 mm 2  and approximately 25 mm 2 ; and 
 
 a magnetizing unit that can selectively magnetize the magnetic material, wherein the magnetizing unit is mounted adjacent to the exterior cylindrical surface of the rotor, the magnetizing unit comprising:
 a plurality of magnetizing poles each having an end adjacent to the exterior cylindrical surface of the rotor; and 
 a corresponding plurality of magnetizing coils each wound around a respective magnetizing pole. 
 
 
   
   
     14. The motor of  claim 13 , wherein the plurality of conductive bars comprises between 24 and 30 conductive bars in the rotor. 
   
   
     15. The motor of  claim 14 , wherein the stator has 24 slots. 
   
   
     16. The motor of  claim 13  , wherein the magnetic material comprises a plurality of bands of material that are mounted on the cylindrical core along the axial direction. 
   
   
     17. A compressor comprising the motor of  claim 14 . 
   
   
     18. A motor, comprising:
 a stator; 
 a rotor mounted inside the stator, the rotor comprising:
 a cylindrical rotor core having a diameter of between approximately 55 mm and approximately 60 mm; 
 a magnetic material mounted on an exterior surface of the cylindrical rotor core so as to define an exterior cylindrical surface of the rotor; and 
 a plurality of conductive bars mounted around the circumference of the cylindrical rotor core, wherein the number of conductive bars is between 24 and 30; and 
 
 a magnetizing unit that can selectively magnetize the magnetic material, wherein the magnetizing unit is mounted adjacent to the exterior cylindrical surface of the rotor, the magnetizing unit comprising:
 a plurality of magnetizing poles each having an end adjacent to the exterior cylindrical surface of the rotor; and 
 a corresponding plurality of magnetizing coils each wound around a respective magnetizing pole. 
 
 
   
   
     19. The motor of  claim 18 , wherein the stator has 24 slots. 
   
   
     20. The motor of  claim 18 , wherein the magnetic material comprises a plurality of bands of material that are mounted on the cylindrical core along the axial direction. 
   
   
     21. A compressor comprising the motor of  claim 18 .